/*
 * $Id: debug.cc,v 1.109 2008/02/26 18:43:30 rousskov Exp $
 *
 * DEBUG: section 0     Debug Routines
 * AUTHOR: Harvest Derived
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"
#include "Debug.h"
#include "SquidTime.h"

int Debug::Levels[MAX_DEBUG_SECTIONS];
int Debug::level;

static char *debug_log_file = NULL;
static int Ctx_Lock = 0;
static const char *debugLogTime(void);
static void ctx_print(void);
#if HAVE_SYSLOG
#ifdef LOG_LOCAL4
static int syslog_facility = 0;
#endif
static void _db_print_syslog(const char *format, va_list args);
#endif
static void _db_print_stderr(const char *format, va_list args);
static void _db_print_file(const char *format, va_list args);

#ifdef _SQUID_MSWIN_
SQUIDCEXTERN LPCRITICAL_SECTION dbg_mutex;
typedef BOOL (WINAPI * PFInitializeCriticalSectionAndSpinCount) (LPCRITICAL_SECTION, DWORD);

#endif

void
#if STDC_HEADERS
_db_print(const char *format,...)
{
#else
_db_print(va_alist)
va_dcl
{
    const char *format = NULL;
#endif

    LOCAL_ARRAY(char, f, BUFSIZ);
    va_list args1;
#if STDC_HEADERS

    va_list args2;
    va_list args3;
#else
#define args2 args1
#define args3 args1
#endif
#ifdef _SQUID_MSWIN_
    /* Multiple WIN32 threads may call this simultaneously */

    if (!dbg_mutex)
    {
        HMODULE krnl_lib = GetModuleHandle("Kernel32");
        PFInitializeCriticalSectionAndSpinCount InitializeCriticalSectionAndSpinCount = NULL;

        if (krnl_lib)
            InitializeCriticalSectionAndSpinCount =
                (PFInitializeCriticalSectionAndSpinCount) GetProcAddress(krnl_lib,
                        "InitializeCriticalSectionAndSpinCount");

        dbg_mutex = static_cast<CRITICAL_SECTION*>(xcalloc(1, sizeof(CRITICAL_SECTION)));

        if (InitializeCriticalSectionAndSpinCount) {
            /* let multiprocessor systems EnterCriticalSection() fast */

            if (!InitializeCriticalSectionAndSpinCount(dbg_mutex, 4000)) {
                if (debug_log) {
                    fprintf(debug_log, "FATAL: _db_print: can't initialize critical section\n");
                    fflush(debug_log);
                }

                fprintf(stderr, "FATAL: _db_print: can't initialize critical section\n");
                abort();
            } else
                InitializeCriticalSection(dbg_mutex);
        }
    }

    EnterCriticalSection(dbg_mutex);
#endif
    /* give a chance to context-based debugging to print current context */

    if (!Ctx_Lock)
        ctx_print();

#if STDC_HEADERS

    va_start(args1, format);

    va_start(args2, format);

    va_start(args3, format);

#else

    format = va_arg(args1, const char *);

#endif

    snprintf(f, BUFSIZ, "%s| %s",
             debugLogTime(),
             format);

    _db_print_file(f, args1);

    _db_print_stderr(f, args2);

#if HAVE_SYSLOG

    _db_print_syslog(format, args3);

#endif
#ifdef _SQUID_MSWIN_

    LeaveCriticalSection(dbg_mutex);

#endif

    va_end(args1);

#if STDC_HEADERS

    va_end(args2);

    va_end(args3);

#endif
}

static void
_db_print_file(const char *format, va_list args) {
    if (debug_log == NULL)
        return;

    /* give a chance to context-based debugging to print current context */
    if (!Ctx_Lock)
        ctx_print();

    vfprintf(debug_log, format, args);

    if (!Config.onoff.buffered_logs)
        fflush(debug_log);
}

static void
_db_print_stderr(const char *format, va_list args) {
    if (opt_debug_stderr < Debug::level)
        return;

    if (debug_log == stderr)
        return;

    vfprintf(stderr, format, args);
}

#if HAVE_SYSLOG
static void
_db_print_syslog(const char *format, va_list args) {
    LOCAL_ARRAY(char, tmpbuf, BUFSIZ);
    /* level 0,1 go to syslog */

    if (Debug::level > 1)
        return;

    if (0 == opt_syslog_enable)
        return;

    tmpbuf[0] = '\0';

    vsnprintf(tmpbuf, BUFSIZ, format, args);

    tmpbuf[BUFSIZ - 1] = '\0';

    syslog(Debug::level == 0 ? LOG_WARNING : LOG_NOTICE, "%s", tmpbuf);
}

#endif /* HAVE_SYSLOG */

static void
debugArg(const char *arg) {
    int s = 0;
    int l = 0;
    int i;

    if (!strncasecmp(arg, "ALL", 3)) {
        s = -1;
        arg += 4;
    } else {
        s = atoi(arg);

        while (*arg && *arg++ != ',')

            ;
    }

    l = atoi(arg);
    assert(s >= -1);

    if(s >= MAX_DEBUG_SECTIONS)
        s = MAX_DEBUG_SECTIONS-1;

    if (l < 0)
        l = 0;

    if (l > 10)
        l = 10;

    if (s >= 0) {
        Debug::Levels[s] = l;
        return;
    }

    for (i = 0; i < MAX_DEBUG_SECTIONS; i++)
        Debug::Levels[i] = l;
}

static void
debugOpenLog(const char *logfile) {
    if (logfile == NULL) {
        debug_log = stderr;
        return;
    }

    if (debug_log_file)
        xfree(debug_log_file);

    debug_log_file = xstrdup(logfile);	/* keep a static copy */

    if (debug_log && debug_log != stderr)
        fclose(debug_log);

    debug_log = fopen(logfile, "a+");

    if (!debug_log) {
        fprintf(stderr, "WARNING: Cannot write log file: %s\n", logfile);
        perror(logfile);
        fprintf(stderr, "         messages will be sent to 'stderr'.\n");
        fflush(stderr);
        debug_log = stderr;
    }

#ifdef _SQUID_WIN32_
    setmode(fileno(debug_log), O_TEXT);

#endif
}

#if HAVE_SYSLOG
#ifdef LOG_LOCAL4

static struct syslog_facility_name {
    const char *name;
    int facility;
}

syslog_facility_names[] = {

#ifdef LOG_AUTH
                              {
                                  "auth", LOG_AUTH
                              },
#endif
#ifdef LOG_AUTHPRIV
                              {
                                  "authpriv", LOG_AUTHPRIV
                              },
#endif
#ifdef LOG_CRON
                              {
                                  "cron", LOG_CRON
                              },
#endif
#ifdef LOG_DAEMON
                              {
                                  "daemon", LOG_DAEMON
                              },
#endif
#ifdef LOG_FTP
                              {
                                  "ftp", LOG_FTP
                              },
#endif
#ifdef LOG_KERN
                              {
                                  "kern", LOG_KERN
                              },
#endif
#ifdef LOG_LPR
                              {
                                  "lpr", LOG_LPR
                              },
#endif
#ifdef LOG_MAIL
                              {
                                  "mail", LOG_MAIL
                              },
#endif
#ifdef LOG_NEWS
                              {
                                  "news", LOG_NEWS
                              },
#endif
#ifdef LOG_SYSLOG
                              {
                                  "syslog", LOG_SYSLOG
                              },
#endif
#ifdef LOG_USER
                              {
                                  "user", LOG_USER
                              },
#endif
#ifdef LOG_UUCP
                              {
                                  "uucp", LOG_UUCP
                              },
#endif
#ifdef LOG_LOCAL0
                              {
                                  "local0", LOG_LOCAL0
                              },
#endif
#ifdef LOG_LOCAL1
                              {
                                  "local1", LOG_LOCAL1
                              },
#endif
#ifdef LOG_LOCAL2
                              {
                                  "local2", LOG_LOCAL2
                              },
#endif
#ifdef LOG_LOCAL3
                              {
                                  "local3", LOG_LOCAL3
                              },
#endif
#ifdef LOG_LOCAL4
                              {
                                  "local4", LOG_LOCAL4
                              },
#endif
#ifdef LOG_LOCAL5
                              {
                                  "local5", LOG_LOCAL5
                              },
#endif
#ifdef LOG_LOCAL6
                              {
                                  "local6", LOG_LOCAL6
                              },
#endif
#ifdef LOG_LOCAL7
                              {
                                  "local7", LOG_LOCAL7
                              },
#endif
                              {
                                  NULL, 0
                              }
                          };

#endif

void
_db_set_syslog(const char *facility) {
    opt_syslog_enable = 1;
#ifdef LOG_LOCAL4
#ifdef LOG_DAEMON

    syslog_facility = LOG_DAEMON;
#else

    syslog_facility = LOG_LOCAL4;
#endif

    if (facility) {

        struct syslog_facility_name *n;

        for (n = syslog_facility_names; n->name; n++) {
            if (strcmp(n->name, facility) == 0) {
                syslog_facility = n->facility;
                return;
            }
        }

        fprintf(stderr, "unknown syslog facility '%s'\n", facility);
        exit(1);
    }

#else
    if (facility)
        fprintf(stderr, "syslog facility type not supported on your system\n");

#endif
}

#endif

void
Debug::parseOptions(char const *options) {
    int i;
    char *p = NULL;
    char *s = NULL;

    if(Config.onoff.debug_override_X) {
        debugs(0, 9, "command-line -X overrides: " << options);
        return;
    }

    for (i = 0; i < MAX_DEBUG_SECTIONS; i++)
        Debug::Levels[i] = 0;

    if (options) {
        p = xstrdup(options);

        for (s = strtok(p, w_space); s; s = strtok(NULL, w_space))
            debugArg(s);

        xfree(p);
    }
}

void
_db_init(const char *logfile, const char *options) {
    Debug::parseOptions(options);

    debugOpenLog(logfile);

#if HAVE_SYSLOG && defined(LOG_LOCAL4)

    if (opt_syslog_enable)
        openlog(appname, LOG_PID | LOG_NDELAY | LOG_CONS, syslog_facility);

#endif /* HAVE_SYSLOG */

}

void
_db_rotate_log(void) {
    int i;
    LOCAL_ARRAY(char, from, MAXPATHLEN);
    LOCAL_ARRAY(char, to, MAXPATHLEN);
#ifdef S_ISREG

    struct stat sb;
#endif

    if (debug_log_file == NULL)
        return;

#ifdef S_ISREG

    if (stat(debug_log_file, &sb) == 0)
        if (S_ISREG(sb.st_mode) == 0)
            return;

#endif

    /*
     * NOTE: we cannot use xrename here without having it in a
     * separate file -- tools.c has too many dependencies to be
     * used everywhere debug.c is used.
     */
    /* Rotate numbers 0 through N up one */
    for (i = Config.Log.rotateNumber; i > 1;) {
        i--;
        snprintf(from, MAXPATHLEN, "%s.%d", debug_log_file, i - 1);
        snprintf(to, MAXPATHLEN, "%s.%d", debug_log_file, i);
#ifdef _SQUID_MSWIN_

        remove
            (to);

#endif

        rename(from, to);
    }

    /*
     * You can't rename open files on Microsoft "operating systems"
     * so we close before renaming.
     */
#ifdef _SQUID_MSWIN_
    if (debug_log != stderr)
        fclose(debug_log);

#endif
    /* Rotate the current log to .0 */
    if (Config.Log.rotateNumber > 0) {
        snprintf(to, MAXPATHLEN, "%s.%d", debug_log_file, 0);
#ifdef _SQUID_MSWIN_

        remove
            (to);

#endif

        rename(debug_log_file, to);
    }

    /* Close and reopen the log.  It may have been renamed "manually"
     * before HUP'ing us. */
    if (debug_log != stderr)
        debugOpenLog(Config.Log.log);
}

static const char *
debugLogTime(void) {

    time_t t = getCurrentTime();

    struct tm *tm;
    static char buf[128];
    static time_t last_t = 0;

    if (Debug::level > 1) {
        char buf2[128];
        tm = localtime(&t);
        strftime(buf2, 127, "%Y/%m/%d %H:%M:%S", tm);
        buf2[127] = '\0';
        snprintf(buf, 127, "%s.%03d", buf2, (int) current_time.tv_usec / 1000);
        last_t = t;
    } else if (t != last_t) {
        tm = localtime(&t);
        strftime(buf, 127, "%Y/%m/%d %H:%M:%S", tm);
        last_t = t;
    }

    buf[127] = '\0';
    return buf;
}

void
xassert(const char *msg, const char *file, int line) {
    debugs(0, 0, "assertion failed: " << file << ":" << line << ": \"" << msg << "\"");

    if (!shutting_down)
        abort();
}

/*
 * Context-based Debugging
 *
 * Rationale
 * ---------
 * 
 * When you have a long nested processing sequence, it is often impossible
 * for low level routines to know in what larger context they operate. If a
 * routine coredumps, one can restore the context using debugger trace.
 * However, in many case you do not want to coredump, but just want to report
 * a potential problem. A report maybe useless out of problem context.
 * 
 * To solve this potential problem, use the following approach:
 * 
 * int
 * top_level_foo(const char *url)
 * {
 *      // define current context
 *      // note: we stack but do not dup ctx descriptions!
 *      Ctx ctx = ctx_enter(url);
 *      ...
 *      // go down; middle_level_bar will eventually call bottom_level_boo
 *      middle_level_bar(method, protocol);
 *      ...
 *      // exit, clean after yourself
 *      ctx_exit(ctx);
 * }
 * 
 * void
 * bottom_level_boo(int status, void *data)
 * {
 *      // detect exceptional condition, and simply report it, the context
 *      // information will be available somewhere close in the log file
 *      if (status == STRANGE_STATUS)
 *      debugs(13, 6, "DOS attack detected, data: " << data);
 *      ...
 * }
 * 
 * Current implementation is extremely simple but still very handy. It has a
 * negligible overhead (descriptions are not duplicated).
 * 
 * When the _first_ debug message for a given context is printed, it is
 * prepended with the current context description. Context is printed with
 * the same debugging level as the original message.
 * 
 * Note that we do not print context every type you do ctx_enter(). This
 * approach would produce too many useless messages.  For the same reason, a
 * context description is printed at most _once_ even if you have 10
 * debugging messages within one context.
 * 
 * Contexts can be nested, of course. You must use ctx_enter() to enter a
 * context (push it onto stack).  It is probably safe to exit several nested
 * contexts at _once_ by calling ctx_exit() at the top level (this will pop
 * all context till current one). However, as in any stack, you cannot start
 * in the middle.
 * 
 * Analysis: 
 * i)   locate debugging message,
 * ii)  locate current context by going _upstream_ in your log file,
 * iii) hack away.
 *
 *
 * To-Do: 
 * -----
 *
 *       decide if we want to dup() descriptions (adds overhead) but allows to
 *       add printf()-style interface
 *
 * implementation:
 * ---------------
 *
 * descriptions for contexts over CTX_MAX_LEVEL limit are ignored, you probably
 * have a bug if your nesting goes that deep.
 */

#define CTX_MAX_LEVEL 255

/*
 * produce a warning when nesting reaches this level and then double
 * the level
 */
static int Ctx_Warn_Level = 32;
/* all descriptions has been printed up to this level */
static int Ctx_Reported_Level = -1;
/* descriptions are still valid or active up to this level */
static int Ctx_Valid_Level = -1;
/* current level, the number of nested ctx_enter() calls */
static int Ctx_Current_Level = -1;
/* saved descriptions (stack) */
static const char *Ctx_Descrs[CTX_MAX_LEVEL + 1];
/* "safe" get secription */
static const char *ctx_get_descr(Ctx ctx);


Ctx
ctx_enter(const char *descr) {
    Ctx_Current_Level++;

    if (Ctx_Current_Level <= CTX_MAX_LEVEL)
        Ctx_Descrs[Ctx_Current_Level] = descr;

    if (Ctx_Current_Level == Ctx_Warn_Level) {
        debugs(0, 0, "# ctx: suspiciously deep (" << Ctx_Warn_Level << ") nesting:");
        Ctx_Warn_Level *= 2;
    }

    return Ctx_Current_Level;
}

void
ctx_exit(Ctx ctx) {
    assert(ctx >= 0);
    Ctx_Current_Level = (ctx >= 0) ? ctx - 1 : -1;

    if (Ctx_Valid_Level > Ctx_Current_Level)
        Ctx_Valid_Level = Ctx_Current_Level;
}

/*
 * the idea id to print each context description at most once but provide enough
 * info for deducing the current execution stack
 */
static void
ctx_print(void) {
    /* lock so _db_print will not call us recursively */
    Ctx_Lock++;
    /* ok, user saw [0,Ctx_Reported_Level] descriptions */
    /* first inform about entries popped since user saw them */

    if (Ctx_Valid_Level < Ctx_Reported_Level) {
        if (Ctx_Reported_Level != Ctx_Valid_Level + 1)
            _db_print("ctx: exit levels from %2d down to %2d\n",
                      Ctx_Reported_Level, Ctx_Valid_Level + 1);
        else
            _db_print("ctx: exit level %2d\n", Ctx_Reported_Level);

        Ctx_Reported_Level = Ctx_Valid_Level;
    }

    /* report new contexts that were pushed since last report */
    while (Ctx_Reported_Level < Ctx_Current_Level) {
        Ctx_Reported_Level++;
        Ctx_Valid_Level++;
        _db_print("ctx: enter level %2d: '%s'\n", Ctx_Reported_Level,
                  ctx_get_descr(Ctx_Reported_Level));
    }

    /* unlock */
    Ctx_Lock--;
}

/* checks for nulls and overflows */
static const char *
ctx_get_descr(Ctx ctx) {
    if (ctx < 0 || ctx > CTX_MAX_LEVEL)
        return "<lost>";

    return Ctx_Descrs[ctx] ? Ctx_Descrs[ctx] : "<null>";
}

int Debug::TheDepth = 0;

std::ostream &
Debug::getDebugOut() {
    assert(TheDepth >= 0);
    ++TheDepth;
    if (TheDepth > 1) {
        assert(CurrentDebug);
        *CurrentDebug << std::endl << "reentrant debuging " << TheDepth << "-{";
    } else {
        assert(!CurrentDebug);
        CurrentDebug = new std::ostringstream();
        // set default formatting flags
        CurrentDebug->setf(std::ios::fixed);
        CurrentDebug->precision(2);
    }
    return *CurrentDebug;
}

void
Debug::finishDebug() {
    assert(TheDepth >= 0);
    assert(CurrentDebug);
    if (TheDepth > 1) {
        *CurrentDebug << "}-" << TheDepth << std::endl;
    } else {
        assert(TheDepth == 1);
        _db_print("%s\n", CurrentDebug->str().c_str());
        delete CurrentDebug;
        CurrentDebug = NULL;
    }
    --TheDepth;
}

// Hack: replaces global ::xassert() to debug debugging assertions
// Relies on assert macro calling xassert() without a specific scope.
void
Debug::xassert(const char *msg, const char *file, int line) {
	
    if (CurrentDebug) {
        *CurrentDebug << "assertion failed: " << file << ":" << line <<
            ": \"" << msg << "\"";
    }
    abort();
}

std::ostringstream (*Debug::CurrentDebug)(NULL);
